1. Field of the Invention
The present invention refers to rice mills and, more particularly, it is related to a fully pneumatic rice mill having means for the pneumatic coneyance of both the grain and the by-products and waste materials.
2. Description of the Prior Art
Rice mills constitute a very well known type of equipment and generally comprise grain feed means, grain prehusking means connected to said grain feed means, grain husking means connected to said grain prehusking means, husk removing means connected to said grain husking means, paddy removing means connected to said husk removing means, grain polishing and whitening means connected to said paddy removing means, grain classifying means connected to said polishing and whitening means and bin means connected to said classifying means, as well as grain elevating means for conveying the grain from one of the units to the other and pneumatic cyclonic separating means for removing light materials from the various pieces of equipment described above.
Rice mills are generally arranged in several floors, whereby the cycle of manufacture involves the elevation of grain several times from the ground floor to the top or intermediate floors, inasmuch as in the normal arrangement of rice mills, the grain prehusking means are at the upper floor, the grain husking means and husk separating means are at the intermediate floor and the paddy removing means are at the lower floor, and thereafter the grain polishing and whitening means are again arranged at the intermediate floor, and the grain classifying means are also arranged at the intermediate floor, whereas the bin means for collecting the grains already classified are arranged between the intermediate and the ground floor.
As the grain feed means comprises a receiving hopper generally located underground, it is necessary to elevate the grains from said feed means to the top floor and, for this purpose, as well as for the purpose of elevating the grain from the paddy removing means to the grain whitening and polishing means and thereafter to again elevate the grain from the whitening and polishing means to the grain classifying means, suitable elevators become necessary. In prior art rice mills, bucket type elevators are normally used, inasmuch as it has been considered up to the present time that by using pneumatic conveyors for elevating the grain, the speed achieved by said grain when discharged into the various respective pieces of equipment is so great that a very large proportion of breakage occurs, which renders pneumatic conveyors quite inadequate for transporting the grain within a rice mill.
For instance, a well known prior art rice mill, such as the Schule Burma mill, manufactured by Schule AG, of Germany, generally uses a group of bucket elevators to elevate the grain, particularly when several stages of prehusking, husking and whitening and polishing machines are used, whereby the grain is always picked up at the bottom of the mill by the bucket elevators and is discharged at the top, to be distributed among the various pieces of equipment, so as to avoid unduly high speeds of the grain when reaching the mechanical parts of the machines, thus avoiding a large proportion of breakage. Also, another very well known prior art rice mill such as the Satake rice mill, manufactured by Satake Engineering Co., Ltd. of Japan, also uses large capacity bucket elevators having distributing bins on the top, in order to distribute the grain amongst the various pieces of equipment, and several of such large capacity bucket elevators are installed throughout the mill in order to achieve the movement of the grain as necessary.
One other very well known type of mill is the Remo mill manufactured in Mexico by Refaccionaria de Molinos, S.A. In this type of mill, also a group of bucket elevators is used in order to convey the grain from the equipment installed at the ground floor up to the equipment installed at the intermediate or top floors, so as to accomplish the same goal stated above.
All the well known prior art mills, such as the three above described mills manufactured by Schule AG, Stake Engineering Company, Limited and Refaccionaria de Molinos, S.A., use bucket type elevators for the grain, because again, it has been considered up to the present time that the pneumatic conveyance of the grain causes serious problems and a large proportion of breakage when the grain reaches a relatively high velocity at the different pieces of equipment wherein it violently impacts against the mechanical parts of such equipment, thus breaking and producing a large proportion of reject grain.
While all rice mills known in the prior art do contain pneumatic conveyance means, these pneumatic conveyance means are restricted merely to the by-products and waste materials, namely, to remove the husk from the husk removing means, to remove the dust and husk from the grain husking means, to remove the flour and bran produced in the grain whitening and polishing means, to remove flour from the grain classifying means and also from the bin means for storage of the grain already fully treated by the mill. However, as mentioned above, these pneumatic means have been restricted only to the by-products and waste materials and have not been applied up to the present time to the conveyance of the grain itself, in view of the above mentioned drawback.
Therefore, for long it has been sought to solve the above problem, because pneumatic conveyance is a highly efficient and economic means of transporting the grain within a rice mill, with a consumption of only a fraction of the energy consumed by the traditional bucket type elevating means, whereby numerous efforts have been made to try to adapt pneumatic conveyor systems for conveying the grains in a rice mill, without much success, however, up to the present date.
The problem of grain breakage in pneumatic conveyors used in rice mills, therefore, has remained up to the present date without any plausible solution, and all rice mills in existence in the present market use bucket type elevators for conveying the grain from one section to another, without any effort having been made to adapt any type of pneumatic conveyor for the conveyance of the grain itself. The pneumatic systems which have been used have been restricted to the by-products and waste materials such as flour, bran, husk, dust and the like.